In various parts of the world, a typical residential building receives potable water through a single water supply line connected to a water main forming part of a local distribution system. To generate hot water from the potable water for various domestic uses including showers and baths, a water heater may be utilized to heat the potable water above its initial temperature as received from the water main.
Commercially available water heaters generally rely on thermal energy obtained from combustion of fossil fuels such as natural gas to heat water, and are normally intended for installation indoors, such as in the basement of a home. Similar to other machines and devices designed to perform fossil fuel combustion, for operation a water heater requires, in addition to a source of fossil fuels, a continuous supply of combustion air containing a level of oxygen required for the combustion, and creates a stream of flue gas having an elevated level of carbon dioxide as generated from the combustion. To ensure that operation of a water heater indoors does not deplete oxygen levels and elevate carbon dioxide levels beyond those acceptable for human inhabitation, a water heater is typically supplied with a duct work for communicating the generated flue gas to outdoors, and supplying a combustion air from outdoors to the water heater.
A water heater usually includes a cylindrical body having a tank for storage of water to be heated, a cold water inlet, a hot water outlet, an apparatus for applying heat to the stored water including a natural gas inlet, control valves and associated thermostat mechanisms, and a combustion chamber in which the natural gas is burned, and which is adapted to conduct or convey the heat of combustion to the stored water. A water heater may further include an upper body portion provided with a combustion air inlet duct for receiving a combustion air, as well as a flue gas outlet duct for expelling a flue gas generated inside the water heater, and which is spaced from the inlet duct. It is the function of a duct work to establish fluid communication between the inlet and outlet ducts and an outdoor atmosphere.
The applicant has appreciated that absent industry standard dimensions and placement of the outlet/inlet ducts on different water heaters manufactured by different companies, installation of the duct work may require custom fabrications and modifications for each different water heaters. In particular, with duct works provided a pair of conduits for connecting to the respective outlet/inlet ducts, a single coaxial double wall pipes for traversing a wall of a residential building and a gas joint for fluidically coupling the conduits and the coaxial pipe, modifications may be required to be introduced various physical changes to the conduits, joint and/or coaxial pipe, thereby increasing associated installation time and costs.